Natural History of Volcanos and Earthquakes. 77 



ture, or at all events, one which varies only 4*^.5 Fahr., in a whole 

 year. Since the conjecture is probable that the lias and the va- 

 riegated marl present the first entirely impermeable strata, we may 

 also conclude, that not only the chalk formation, but also the 

 greeti sand, which is equally fissured, are filled by the reservoir, 

 and that its bottom is formed by the above mentioned impermea- 

 ble strata. Lastly, the high temj erature of what are called the 

 warm Pader springs (54^.5-01^.25 Fahr.) indicates also an or- 

 igin from a greater depth, if they do not flow in distinct chan- 

 nelSj but come from warm streams, which rise from the base of 

 the reservoir. 



The copious springs, which rise on the western declivity of 

 the Teutoburger Waldy owe their abundance of water, even in 

 dry seasons, to these vast subterraneous reservoirs; and w^hat is 

 derived from these reservoirs, is abundantly replaced in the rainy 

 reasons, when nearly all the water collected ni a district so much 

 fissured, penetrates into the interior. 



These large masses of water, whose temperature exceeds, by 

 several degrees the average one of the district under which they 

 are collected, and which brings so much the more heat to their 

 surface the deeper they penetrate, have doubtless the effect of 

 warming the hills under which they exist. It is therefore per- 

 haps a phenomena of universal occurrence, that all chalk hills^ 

 which are much fissured, and into which brooks, riv^ers, and most 

 of the meteoric water sink, maintain a relatively higher temper- 

 ature. The Pader springs alone, however, show how inexhaust- 

 ible must be the sources which warm such vast masses of water. 

 These springs furnish in a year at least 8688 millions of cubic 

 feet of water, whose average temperature exceeds by at least 

 6^,75 Fahr., the average temperature of the ground at Pader- 

 horn^ and this excess would melt a cube of ice, having a side of 

 934 feet. This heat is iYrev^ocably withdrawn from the interior, 

 and yet the thermal springs of Paderhorn have sustained no 

 diminution of heat from lime immemorial.* Chemical processes, 

 which could there give rise to such inexhaustible sources of heat 

 in the youngest secondary formations, must be, or have been, 

 carried on to a great extent indeed ! 



* By far the greater number of the remaining copious springs, which rise on the 

 western declivity of the Tutohurger Wald^ are also thermal ones. Some, for in-^ 

 stance, in Lipps^prlng attain a temperature of 54^.5. 



